/Engine/Source/Editor/BlueprintGraph/Classes/BlueprintTypePromotion.h
Returns true if A can be promoted to type B correctly, or if the types are equal
static bool IsValidPromotion ( const [FEdGraphPinType](API\Runtime\Engine\EdGraph\FEdGraphPinType) & A, const [FEdGraphPinType](API\Runtime\Engine\EdGraph\FEdGraphPinType) & B )